Albert Einstein & the Alexanderson high frequency alternator

A century ago this November, Albert Einstein published 10 equations that rocked the foundations of physics and changed how we view the universe. We call them “the theory of relativity”.

In 1921, Einstein toured a high-power transoceanic radio station in New Brunswick, New Jersey. It was operated by the Radio Corporation of America, which was co-founded by GE and featured a high-frequency alternator designed by GE engineer Ernst Alexanderson in 1918.

The Alexanderson high frequency alternator at the New Brunswick radio station during military inspection. The machine, developed by GE engineer Ernst Alexanderson, was a valuable communication tool during World War I. Image credit: Museum of Innovation and Science Schenectady

Einstein reportedly “expressed great surprise and interest at the high perfection” of American radio development. “To demonstrate the efficiency of radio communication, Prof. Einstein was asked to send a message to the station at Nauen, Germany,” a news paper wrote. “He did and in exactly six minutes received the following reply: Many thanks and reciprocations. Most hearty greetings to the great German scientist. Officer in charge POZ.”

Einstein outside the RCA broadcast center in New Brunswick, New Jersey. Einstein and Steinmetz (in white suit) stand in the center. GE’s Irving Langmuir is third to the right from Steinmetz. In 1932, he won the Nobel Prize in Chemistry for his work that led to early coronary artery imaging. All images credit: Museum of Innovation and Science in Schenectady

World Heritage Grimeton Radio Station with the call signal “SAQ” is the last remaining and fully functional high frequency Alexanderson Alternator in the world. SAQ sent its first transmission on December 1st, 1924 on the frequency 16.7 kHz, later adjusted to 17.2 kHz. The radio waves were generated by the alternator – a rotating electromechanical generator – with a transmitting power of 200 kW.